To date, bearing assemblies are supplied as individual parts and installed and assembled on-site in a tidal turbine. In such case the individual elements are usually only sealed on-site. Since tidal turbines are used under water, the seal-tightness of the bearing is particularly important because moisture can very easily enter and damage the bearing in the long term. After the installation of the bearing assembly into the tidal turbine, the seal-tightness of the bearing must therefore be tested. This involves a great expense since the testing is performed on the tidal turbine and not during the manufacturing of the bearing.